Exhaust machine



Oct. 8, I957 J. B. YODER EXHAUST MACHINE Filed Dec. 23, 1954 lhven' tror i doe B.YOdT", b5 W His Atbo1-ne3 United States Patent Office 2,808,857 Patented Oct. 8, 1957 EXHAUST MACHINE Joe B. Yoder, Mayfield Heights, Ohio, assignor to General Electric Company, a corporation of New York Application December 23, 1954, Serial No. 477,293

Claims. (Cl. 141- 66) My invention relates to apparatus for exhausting and gas filling electric lamps, discharge and similar sealed devices, and more particularly to automatic high-production exhaust machines for filling lamps with measured amounts of gas.

The invention is particularly applicable to rotary high speed exhaust machines having permanent pipe line connections between exhaust heads near the periphery of the machine and a main rotary valve located adjacent the axis of rotation. In machines of this type, when atmospheric gases enter an exhaust head, contamination of the pipe line occurs at least as far back as the rotary valve, and, in instances where the gas filling pressure is less than atmospheric, contamination of the gas filling lines beyond the rotary valve may also occur.

The object of the invention is to minimize the contamination and loss of gas which results when a leaky electrical device or lamp is advanced through the full cycle of such machines.

Another object is to provide an automatic exhaust and gas filling machine including means for substantially eliminating contamination of the main valving means when a leaky lamp is processed and permitting convenient adjustment of the filling gas pressure.

A feature of the invention is the filling of discharge lamps to a pressure less than atmospheric from a storage reservoir repeatedly filled to a pressure higher than atmospheric. Such an arrangement limits the extent to which the atmosphere can back up into the gas lines when a leaky lamp is connected thereto and also limits the loss of filling gas under such circumstances to the quantity of gas required to fill a single lamp.

In a rotary exhaust machine embodying the invention, the exhausting and filling operations are controlled by a rotary valve located about the center column of the machine, and separate conduits extend from the rotary valve to exhaust heads about the periphery of the machine. An intermediate gas metering reservoir is provided between the high pressure gas source and the rotary valve. This reservoir, which is preferably only momentarily connected to the exhaust heads by the rotary valve, is of a size holding a charge of gas sufficient to fill the line to an exhaust head and the lamp retained thereby to the desired subatmospheric pressure. A salient feature is that the gas within the reservoir is introduced therein through a very small restriction and is built up slowly to a supraatmospheric pressure before being released to the exhaust head to expand into the lamp to a subatmospheric pressure. Thereservoir is also desirably fitted with means for adjusting its volume to match different sizes of lamps exhausted by the machine.

Further features and advantages of the invention will appear from the following detailed description of preferred embodiments and from the drawing.

In the drawing:

Fig. 1 is a vertical section through an exhaust head and a turret fragment of an exhausting and gas filling machine embodying the invention;

Fig. 2 is a plan view of a segment of the rotary valve of the machine;

Fig. 3 is a vertical section through a lower section of a rotary valve and a modified gas reservoir also embodying the invention; and

Fig. 4, similarly to Fig. 3, shows another modification of a gas reservoir particularly suitable for filling larger sizes of lamps.

Referring to Figs. 1 and 2 of the drawing, a discharge lamp 1 is retained in an exhaust port or head 2 supported by a rotary turret 3. The exhaust head illustrated is one of several mounted on the periphery of turret 3, whereof a half only is shown in Fig. l. The exhaust and gas filling occur automatically during the step-by-step movement of exhaust heads 2 through a succession of work stations, including stations A to D indicated in Fig. 1. As turret 3 rotates, the heads are coupled successively to sources of vacuum and gas through the corresponding rotation of upper section 4 of a ring-shaped rotary valve 5 surrounding center post 6 of the machine. The connections are made when passages 7 and 8, extending from ports in the lower face of upper valve section 4, register with the ports of other passages 9 and 10 in the upper mating face of lower stationary valve section 11. Exhaust is effected through passage 7 which is connected to the exhaust head by conduit 12, and gas filling, through passage 8 and conduit 13.

In the operation of the machine, the lamps are flushed by repeated exhausting and gas filling. The exhaust, which in every case precedes the gas filling, is effected when the passage 7 is positioned at stations such as A, B and D, where it registers with one of the ports of passages 9 in the stationary lower valve section 11, these passages being connected through pipes 14 to a source of vacuum (not shown). At such times, a direct con nection is maintained in known fashion from the lamp through the pinch clamp 15 of the sealing head to conduit 12. This is effected through relaxation of pinch clamp mechanism 16 so that rubber tube 17 joining the main body 18 of the head and conduit 12 takes its normal cylindrical form, thereby opening the passageway therethrough. The lamp 1 receives the full effect of the vacuum source under these conditions and is sealed from the atmosphere by rubber gasket 19 which surrounds exhaust tube 20 of the lamp. A cap 21 screwed onto the main body 18 keeps the rubber gasket 19 under axial compression to hold the lamp firmly and make an airtight seal with the exhaust tube.

The gas filling operation occurs when the port of passage 8 in upper valve section 4 registers with that of passage 10 in lower valve section 11. In the illustrated embodiment, the gas is introduced on the fly, that is, while the exhaust head is indexing, the passage 8 being angularly oifset relative to the exhaust head for this purpose. Accordingly, gas can enter the lamp momentarily only during the very short interval the passage 8 registers with the passage 10. The quantity of gas introduced into the lamp corresponds to the gas char e contained in the metering reservoir formed by passage 10, lateral passage 22 and hollow center 23 of fitting 24 attached to the lower valve section 11. According to a feature of the invention, the metering reservoir is of small volume and the gas therein is supplied at a pressure above atmospheric and much higher than that ultimately desired in the lamp, but less than that of the supply. This manner of supplying gas to the exhaust head substantially eliminates possibility of atmospheric contamination of the gas supply inasmuch as the flow of gas must be outward from the reservoir to the lower pressure atmosphere.

According to another feature of the invention, the highpressure gas, argon for instance, is supplied to the metering reservoir from a high-pressure cylinder by supply pipe 25 through a restriction formed by a wadding 26 of cotton fiber or felt behind a threaded compression plug 27. This restriction is proportioned to pass gas through the threads around the plug 27 and through the compressed wadding 26 at a rate just sufficient to replenish the gas within the metering reservoir to the desired supraatmospheric pressure during the interval between the index of successive exhaust heads into connection therewith. The compression plug may be tightened or loosened to afford a wide range of adjustment of the rate of gas flow into the metering reservoir to suit different lamps and fill pressures.

A further feature of the reservoir is the adjustable rodlike insert 28 which projects into it and enables its volume to be adjusted to fill the lamp 1 properly under the conditions provided. The rod-like insert 28 can be pushed into or withdrawn from the fitting 24 to change the volume of the reservoir and thus provides for quick adjustment of the apparatus in accordance with the different volumes of various types and sizes of lamps or electrical devices handled by the machine. The insert is only slightly smaller than the hollow center 23 of fitting 24 and is sealed into the fitting by packing 29 under pressure exerted by gland 30 through sleeve 31. Insert 28 is of such length that it may be pushed up into connecting passage 22 in lower valve section 11 if required to extend the range of adjustment of the metering reservoir.

By way of example, it is desired to fill a certain lamp,

such as illustrated in the drawing, with argon to a pressure of 30 millimeters of mercury. The restriction including wadding 26 is adjusted such that the metering reservoir is filled to 15 pounds gauge, that is, approximately 30 pounds per square inch absolute at each index. The lamp will then be filled to proper pressure when insert 28 of .123 inch diameter projects 2 inches into fitting 24 and, accordingly, about 1 inch into the reservoir whose bore 23 is .125 inch in diameter.

When the lamp is not being exhausted, exhaust conduit 12 is sealed ofi at one end by rotary valve 5 and at the other end by pinch clamp mechanism 16. This manner of operation is conventional and is desirable in that no gas is lost in charging conduit 12. The usual means, cams for instance (not shown), are provided adjacent the periphery of turret 3 for causing pinch clamp mechanism 16 to squeeze the rubber tube 17 sufiiciently to close off the passage therethrough. The pinch clamp closing operation is effected before the port of passage 8 registers with that of passage 10 and releases the gas charge. The illustrated arrangement is also desirable in order to seal off the gas charge from a mercury diffusion pump (herein indicated in block form at 12') which may be connected in conventional fashion into exhaust conduit 12. It also prevents return movement of gas through conduit 12, which movement could carry contamination into the lamp from a trap normally associated with pump 12.

Gas conduit 13 is never sealed off from the exhaust head, being attached directly to the main body 18 of the head, but cannot normally conduct contamination into the lamp since it is exhausted during the entire period the lamp is being exhausted. At such times, the port of passage 8 at the end of conduit 13 is sealed by the rotary valve.

With the structure which has been described, a leaking lamp or an open exhaust head does not cause a lamp placed in the head in a succeeding cycle of operation, or a succeeding head on turret 3, to be contaminated from the gas supply passage 10 and its metering reservoir, because the higher pressure of gas within the passage and reservoir cause a flow of gas outward from the reservoir. As a result, there is substantially no possibility of the atmosphere penetrating to the reservoir.

When the index from station B to C associated with the introduction on the fly of gas into the lamp is complete, both passages '7 and 8 in upper section 4 of the rotary valve are sealed off. Work station C occupied by head 2 at this time may be used to condition electrodes 32 at opposite ends of the lamp, as by effecting an electric discharge between them. This results in contaminants and gaseous impurities being driven from the electrodes out into the lamp, so that the lamp must again be evacuated and filled. Subsequent evacuation and gas filling may take place at station D and succeeding stations in the same manner as has been described. After the final gas filling operation, the lamp 1 is sealed by fusing off exhaust tube 20 at a point adjacent the top surface of the exhaust head.

Another metering reservoir, according to the invention, is shown in Fig. 3. The reservoir associated with the modified fitting 24' consists, as before, of passages 10 and 22 in rotary valve section 11 and hollow center 23 of fitting 24. It is adjusted in volume by insertion or retraction of rod-like insert 28. The gas supplied to the reservoir, in this embodiment, is controlled by a valve 33 having an operating cycle timed to introduce gas into the reservoir during periods when the reservoir is sealed off from the exhaust head. Gas enters the reservoir when stem 34- of valve 33 is raised from its seat through the energization of control solenoid 35 for a predetermined time interval. The solenoid is suitably timed relative to the machine by the actuation of switch 36 under control of cam 37 on main drive shaft 38 of the machine. The gas travels to the valve seat from supply pipe 25' through a longitudinal passage 39 along the side of valve stem 34, the passage being of small cross section to restrict the flow.

Still another metering reservoir embodying the invention is shown in Fig. 4, and is particularly suitable for supplying the larger volumes of gas required with fluorescent discharge lamps. The reservoir consists of passages 10 and 22 in lower rotary valve section 11, and as much of the hollow interior of flexible tube 41, of synthetic rubber for instance, as is divided off by a restricting plug 42. The gas for charging the reservoir is supplied to the outer end of the rubber tube by supply pipe 43 and passes into the reservoir through the threads about compression plug 27', wedding 26' and fine hole 44 in the center of the restriction 42. The volume of the reservoir is for the most part that space within rubber tube 41 between the end of nipple and restriction 42 inasmuch as the hollow interior of the nipple 40 and the passage 22 in the valve section 11 are almost completely filled with a rod 45. In this arrangement, the volume of the reservoir is adjusted by moving the restriction 42 along the length of the rubber tube 41. The restriction fits tightly enough within the tube to be gripped by the walls with enough force that the pressure of the gas from the supply will not displace it. In this arrangement, variations in the position of rod 45 with respect to nipple 40 do not change the volume of the reservoir but the rod may be provided to limit the rate of flow of gas out of the reservoir into the lamp.

While certain preferred embodiments of the invention have been shown and described in detail, it will be understood that many modifications of the precise manner by which the invention is carried into effect may be made. The appended claims are intended to cover any such modifications as fall within the true spirit and intent of the invention.

I claim:

1. Apparatus for evacuating and gas filling electric devices to sub-atmospheric pressure comprising an exhaust head receiving a device to be processed, a valve including a stationary and a movable member having cooperating valve surfaces, an exhaust conduit leading from a first port in said movable member to said exhaust head, a gas filling conduit leading from a second port in said movable member to said exhaust head, a conduit for connection with a vacuum system terminating in a first port in said stationary member registering with the first port in said movable member, a second port in said stationary member registering with the second port in said movable member, a metering reservoir connected to said second port in said stationary member, a supply line for connecting said reservoir to a high-pressure gas supply, means for adjusting the volume of said reservoir to determine the gas charge therein for filling said device to a predetermined sub-atmospheric pressure, and a restriction interposed between said reservoir and said supply line limiting to a predetermined supra-atmospheric pressure less than that of the said supply the pressure to which said reservoir is gradually filled between registrations of the second ports in said valve members.

2. An exhaust machine for evacuating and gas filling electric devices to sub-atmospheric pressure comprising an indexing turret provided with exhaust heads receiving devices to be processed, a rotary valve including a stationary member and a member movable with said turret, said members have cooperating valve surfaces, an exhaust conduit for each head terminating at one end in a first port in the valve surface of said movable member, and at the other end, in said head, and a gas filling conduit terminating at one end in a second port in the valve surface of said movable member, and at the other end, in said head, a conduit for connection with a vacuum system terminating in a first port in the valve surface of said stationary member registering at an index station of said turret with the first ports in said movable member, a second port in the valve surface of said stationary member registering momentarily during the index travel of said turret with the second ports in said movable member, a metering reservoir connected to said second port in said stationary member, means for adjusting the volume of saidreservoir to determine the gas charge therein for filling said devices to a predetermined sub-atmospheric pressure, a supply line for connecting said reservoir to a high-pressure gas supply and a restriction interposed between said reservoir and said supply line limiting to a predetermined supra-atmospheric pressure less than that of said supply the pressure to which said reservoir is gradually filled between registrations of the second ports in said valve members.

3. An exhaust machine for evacuating and gas filling electric devices to sub-atmospheric pressure comprising an indexing turret provided with exhaust heads receiving devices to be processed, a rotary valve including a stationary member and a member movable with said turret, said members have cooperating valve surfaces, an exhaust conduit for each head terminating at one end in a first port in the valve surface of said movable member, and at the other end, in said head, and a gas filling conduit terminating at one end in a second port in the valve surface of said movable member, and at V the other end, in said head, a conduit for connection with a vacuum system terminating in a first port in the valve surface of said stationary member registering at an index station of said turret with the first ports in said movable member, a second port in the valve surface of said stationary member registering momentarily during the index travel of said turret with the second ports in said movable member, a metering reservoir connected to said second port in said stationary member including a hollow fitting and a movable rod-like insert projecting thereinto for adjusting the volume of said reservoir to determine the gas charge therein for filling said devices to a predetermined sub-atmospheric pressure, a supply line for connecting said reservoir to a high-pressure gas supply, and a restriction interposed between said reservoir and said supply line, said restriction comprising a compressed fibrous wadding and means adjusting the compression thereof to limit to a predetermined supraatmospheric pressure less than that of said supply the pressure to which said reservoir is gradually filled between registrations of the second ports in said valve members.

4. An exhaust machine for evacuating and gas filling electric devices to sub-atmospheric pressure comprising an indexing turret provided with exhaust heads receiving devices to be processed, a rotary valve including a stationary member and a member movable with said turret, said members have cooperating valve surfaces, an exhaust conduit for each head terminating at one end in a first port in the valve surface of said movable member, and at the other end, in said head, and a gas filling conduit terminating at one end in a second port in the valve surface of said movable member, and at the other end, in said head, a conduit for connection with a vacuum system terminating in a first port in the valve surface of said stationary member registering at an index station of said turret with the first ports in said movable member, a second port in the valve surface of said stationary member registering momentarily during the index travel of said turret with the second ports in said movable member, a metering reservoir connected to said second port in said stationary member, and comprising a flexible tube, a supply line for connecting said reservoir to a high-pressure gas supply, and a restricting plug held in place in the flexible tube by engagement with the walls thereof and movable within said tube to adjust the volume of the reservoir between said plug and port to determine the gas charge therein for filling said devices to a predetermined sub-atmospheric pressure, said restricting plug being proportioned to limit to a predetermined supra-atmospheric pressure less than that of said supply the pressure to which said reservoir is gradually filled between registrations of the second ports in said valve members.

5. An exhaust machine for evacuating and gas filling electric devices to sub-atmospheric pressure comprising :xing turret provided with exhaust heads receiving devices to be processed, a rotary valve including a stationary member and a member movable with said turret, said members have cooperating valve surfaces, an exhaust conduit for each head terminating at one end in a first port in the valve surface of said movable member, and at the other end, in said head, and a gas filling conduit terminating at one end ina second port in the valve surface of said movable member, and at the other end, in said head, a conduit for connection with a vacuum system terminating in a first port in the valve surface of said stationary member registering at an index station of said turret with the first ports in said movable member, a second port in the valve surface of said stationary member registering momentarily during the index travel of said turret with the second ports in said movable member, metering reservoir connected to said second port in said stationary member, a conduit for connecting said reservoir to a high-pressure gas supply, a restricting valve interposed. between said reservoir and said last-named conduit, and means opening said valve at predetermined time intervals in order to fill said reservoir to a supraatmospheric pressure less than that of said supply between registrations of the second ports in said valve members, and means for adjusting the volume of said reservoir to determine the gas charge therein for filling said devices to a predetermined sub-atmospheric pressure.

References Cited in the file of this patent UNiTED STATES PATENTS 1,676,302 Van- Der Poel July 10, 1928 2,254,905 Mullan Sept. 2, 1941 2,542,636 DeGroat Feb. 20, 1951 

